Automatic administration instrument for medical use

ABSTRACT

An automatic administration instrument includes a syringe and a partition wall in the syringe which partitions the syringe into different rooms for respectively holding plural kinds of drug solutions or a drug and a drug solution. A partition-wall driver displaces the partition wall and an injection needle is connected to the syringe. A body cap attached to the administration instrument body so as to cover the injection needle. The syringe, the partition wall, and the body cap are configured such that displacing the partition wall dissolves or mixes the drug solutions or the drug and the drug solution in a state that the injection needle is covered by the body cap.

This application is a continuation of application Ser. No. 15/644,105,filed Jul. 7, 2017, now Pat. No. 10/363,368, which is a continuation ofapplication Ser. No. 14/168,509, filed Jan. 30, 2014, now Pat. No.9,731,074, which is a continuation of application Ser. No. 13/587,271,filed Aug. 16, 2012, now U.S. Pat. No. 8,679,055, which is a divisionalapplication of Ser. No. 10/516,395, filed Dec. 2, 2004, now U.S. Pat.No. 8,298,171, which is a 371 application of PCT/JP2003/008391, filedJul. 2, 2003.

TECHNICAL FIELD

The present invention relates to an automatic administration instrumentfor medical use, which is used for administering drug solutions.

BACKGROUND ART

Conventionally, an administration instrument for medical use is oftenused when a drug solution such as growth hormone, insulin, or the likeis administered. Generally, when using the administration instrument, adoctor or a nurse performs administration in a hospital or the like, anda patient or his family performs administration at home. Theadministration is carried out by inserting a needle into some region onthe skin, and the angle of the needle insertion into the skin and thespeed of the needle insertion as well as the speed at which the drugsolution is injected after the needle insertion depend on the skilllevel of a person who performs the administration.

FIG. 5 is a block diagram illustrating the inside of an electricinjector which is currently used in dentistry. The principle ofadministration of drug solutions will be described with reference toFIG. 5. Now, a syringe 103 filled with a drug solution is set in acartridge holder 102 attached to a main body 110.

When pressing a SW1, a motor 111 normally rotates, and the torque isreduced by a reduction gear box 109 which is directly connected to themotor 111 to rotate a reduction gear main-shaft 108 of the reductiongear box 109. An end of the reduction gear main-shaft 108 engages with agear 106 through a rotary disc 107 to rotate the gear 106. Further, thegear 106 engages with a gear 105 and thereby the torque of the gear 106propagates to the gear 105. A gear 105 a is provided coaxially with thegear 105 so as to engage with a rack 104 a which is provided in thelower right half of a push piston 104 from the center thereof. When thegear 105 rotates, the gear 105 a also rotates in the same direction asthe gear 105, and consequently, the push piston 104 is moved in thedirection of the injection needle 113, whereby the drug solution in thesyringe 103 is pushed out of the injection needle 113.

During injecting, air is removed in the above-described operation, andthereafter, the injection needle 113 is inserted into a target region,and the drug solution is administered. In FIG. 5, SW2 denotes a switchfor reverse rotation of the motor 111, and 112 denotes a battery fordriving the motor 111.

Up to this point the conventional electric injector for automaticallyadministering a drug solution has been described.

Next, a typical administration instrument for medical use in which adrug and a drug solution are dissolved and mixed, which hasconventionally been employed, will be described with reference to FIG.6. In the administration instrument for medical use shown in FIG. 6,when it is used, a drug and a drug solution are mixed and dissolved bymanual operation and then injected. In FIG. 6, constituents that aresubstantially identical to those shown in FIG. 5 are given the samereference numerals.

Now, a syringe 103 is set in a cartridge holder 117, and the syringe 103contains a powder preparation 114 and a drug solution 127 which areplaced in different rooms separated by a rubber 116 and a rubber 118. Aninjection needle 113 attached to an end of the syringe 103 is providedwith a needle cap 101. In this state, the injection needle 113 isdirected upward and an injection button 120 is pushed toward theinjection needle 113. Then, the push piston 119 pushes the rubber 118,the rubber then pushes the drug solution 127, and the rubber 116 movestoward the injection needle 113 with the pressure at which the drugsolution 127 is pushed. When the rubber 116 reaches a position slightlyahead of a protrusion 115 of the syringe, the drug solution 127 goesover the rubber 116, passes the syringe protrusion 115, and starts toflow into the room of the powder preparation 114. The injection button120 is further pushed, and then the drug solution 127 continuously flowsinto the room of the powder preparation 114. After all the drug solution127 flows into the room of the powder preparation 114, the rubber 118contacts the rubber 116.

Next, for fully mixing and dissolving them, the injection needle 113 isdirected upward in the above-mentioned state and is slightly shaken.Next, with the injection noodle 113 being directed upward, the needlecap 101 is removed and the injection button 120 is pressed, therebyreleasing air. After the air releasing, the injection needle 113 isinserted into a region of the body at which the drug solution is to beadministered, and the injection button 120 is pressed, whereby the drugsolution is administered into the region. As described above, in theadministration instrument shown in FIG. 16, the processes from themixing and dissolving of the drug and drug solution to theadministration thereof are manually performed.

However, in the conventional administration instrument for medical use,no matter how much a person is skilled in achieving the angle to theskin and the speed during needle insertion as well as the speed ofinjecting the drug solution and the speed of removing the needle afterthe needle insertion, the person who does the administration is merely ahuman being, and therefore, the above-mentioned angle and speeds cannotbe prevented from being varied depending on the physical condition andthe like at that time. Since a person who administers the drug solutionand a person who is given the drug solution are both human beings, thebody sizes are different and the physical conditions at theadministration are not always the same. Therefore, it is difficult toadminister the drug solution in the same manner every time. Therefore,it is not always possible to perform administration with reduced pain.

Particularly, since the electric injector shown in FIG. 5 is a grip typeinjector, the user must grip and support its body by one hand as well askeep on pressing the SW1 throughout administration. Further, since theinjector is large in shape and a battery 112 is heavy in weight, a greatphysical strain is imposed on the person who performs administrationand, therefore, it is difficult to perform self-administration usingthis injector.

Further, in the mixing and dissolving type administration instrumentshown in FIG. 6, since the dissolving operation is manually performed,it is necessary to watch the dissolving condition with great care aswell as perform the dissolving with discretion. Further, proper mixingcannot be performed unless the injection needle is shaken in a verticalorientation even after the dissolving. This is a very troublesome workfor a patient having bad eyesight.

Further, a patient may have a fear about seeing the injection needleuntil just before administration, and this may cause a mental strain tothe patient.

As described above, the needle insertion itself imposes physical andmental strains on the patient and, in some cases, seriously affects thebody of the patient, which might lead to life-threatening danger.

The present invention is made to solve the above-described problems andhas an object of providing an administration instrument for medical usewhich automatically performs needle insertion, administration, andneedle removal, and further, automatically performs dissolving, mixing,and air-releasing when it is a dissolving and mixing type administrationinstrument, and still further, has a construction in which an injectionneedle is kept unseen from the outside until just before needleinsertion, thereby reducing physical and mental strains on patients andrealizing administration under more stable conditions.

DISCLOSURE OF THE INVENTION

An automatic administration instrument for medical use according to thepresent invention is provided with means for automatically inserting aninjection needle into a skin, and means for automatically removing theinjection needle from the skin, and injection is carried out under thestate where a part of the body of the administration instrument ispressed against a body region of a patient to be subjected toadministration. Therefore, an angle, a depth, and a speed at whichneedle insertion or needle removal is carried out can be controlled,thereby reducing a possibility that administration is influenced byvariations in the level of skill, daily physical condition, or body sizeamong individuals.

Further, in the automatic administration instrument for medical useaccording to the present invention, the speed at which the injectionneedle is automatically inserted into the skin or the speed at which theinjection needle is automatically removed from the skin is madevariable, and the amount of drug solution to be injected per unit timeduring administration can be arbitrarily set, and further, the injectionneedle is not visible from the outside until needle insertion iscompleted. Therefore, the pain of the patient to which the drug solutionis administered is reduced during needle insertion, administration, andneedle removal, and the fear of the patient is also reduced, wherebyadministration can be carried out in a stable manner, resulting inreductions in physical and mental burdens.

Further, when the automatic administration instrument for medical useaccording to the present invention is an administration instrument thatemploys plural drug solutions to be mixed, or a drug and a drug solutionto be dissolved and mixed, the mixing or dissolving is automaticallycarried out, and further, a syringe is automatically shaken in theadministration instrument body after the mixing or dissolving iscompleted. Therefore, the patient is relieved of the inconvenience ofthe mixing or dissolving operation, and further, the drug solutions canbe mixed with higher reliability, whereby the drug solution itself canbe used in the optimum state. Further, since air-releasing or the likeis also automatically carried out, it becomes unnecessary to checkair-releasing, thereby reducing the inconvenience of the air-releasingoperation.

Furthermore, in the automatic administration instrument for medical useaccording to the present invention, when the patient forgets aboutattaching the injection needle when performing dissolving oradministration, the operation of pushing out the drug solution isstopped, thereby preventing the risk of cracking of the syringe, inverseleakage of the drug solution, or the like.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an automatic administration instrumentfor medical use according to a first embodiment of the presentinvention.

FIG. 2 is a cross-sectional view of the automatic administrationinstrument for medical use.

FIG. 3 is a cross-sectional view of an automatic administrationinstrument for medical use according to another embodiment of thepresent invention.

FIG. 4 is a block diagram illustrating the automatic administrationinstrument for medical use according the embodiment of the presentinvention.

FIG. 5 is a block diagram illustrating an internal construction of theconventional electric injector.

FIG. 6 is a cross-sectional view of a dissolving and mixing typeautomatic administration instrument for medical use according toconventional example.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, an embodiment of the present invention will be describedwith reference to FIGS. 1 to 4.

FIG. 1 is a perspective view illustrating an external view of anautomatic administration instrument for medical use according to anembodiment of the present invention, FIG. 2 is a cross-sectional viewfor explaining the internal structure of the automatic administrationinstrument for medical use, FIG. 3 is a cross-sectional view forexplaining the internal structure of an automatic administrationinstrument for medical use according to another embodiment of thepresent invention, and FIG. 4 is a block diagram for explaining theembodiment of the present invention.

First of all, the construction and operation of an automaticadministration instrument for medical use which is capable of automaticneedle insertion and automatic needle removal will be described withreference to FIG. 1, FIG. 2, and FIG. 4.

In FIG. 1, reference numeral 18 denotes a body of the automaticadministration instrument for medical use, numeral 17 denotes a switchfor making the administration instrument perform insertion and removalof an injection needle, numeral 21 denotes a body cap that covers theinjection needle, and numeral 20 denotes a skin touch switch fordetecting that the administration instrument body 18 is pressed againsta body region where administration is to be carried out.

In FIG. 2, an inner case 10 to which a syringe 8 filled with a drugsolution 5 is attached is set in the body 18. An injection needle 1 isset at an end of the inner case 10. Further, the injection needle 1 ishoused in a body cap 21 and is invisible from the outside. In FIG. 2,however, the injection needle is visible because FIG. 2 shows theposition of the needle during needle insertion. Further, a battery 2 anda liquid crystal display 3 are also housed in the body cap 21.

Now, the user holds the body 18 by hand, presses the skin touch switch20 against a target region on his/her body, and presses the switch 17.Then, an axis of a motor 16 starts to rotate, and thereby a movablescrew that is directly connected to the axis of the motor 16 rotates. Ascrew thread is formed on the surface of the movable screw 15 so as toengage with a thread formed inside the inner cap 14. The inner cap 14 isengaged with a part of the inner case 10 by screws, and is freelymovable by a predetermined stroke in the longitudinal direction of thebody 18, in the body 18 united with the inner case 10.

That is, in this construction, as the axis of the motor 16 rotates, themovable screw 15 rotates. The rotation is converted into a thrust thatmoves the inner case 10 toward the tip of the injection needle 1 in thebody 18 by the inner cap 14, and consequently, the injection needle 1 isprotruded from the body cap 21 toward the skin and inserted into theskin.

When administration of the drug solution is ended, the motor 16 rotatesbackward, and the injection needle 1 is housed into the body 18. Thatis, the needle 1 is removed from the skin.

It has been known that the higher the speed of inserting and removingthe injection needle is, the lesser the patient feels pain. While inthis embodiment these operations are carried out at an instant of 0.05sec or below during actual administration, the operation speed isvariable and settable by a setting switch 26. Further, a series ofoperations and settings described above are carried out by sendingsignals to a microprocessor 100 shown in FIG. 4 to be judged andinstructed by the microprocessor 100.

Since, for safety, the circuit is constructed so that the actual needleinsertion is not carried out unless the skin touch switch 20 is pressed,the needle insertion cannot be carried out unless the skin touch switch20 is pressed against the target skin region. Further, the needleremoval is carried out by rotating the motor 16 backward after themicroprocessor 100 judges that the administration is completed. Also theneedle removal is carried out at an instant of 0.05 sec or below, likethe needle insertion.

In the above-mentioned construction, the operation of injecting the drugsolution is carried out as follows.

With reference to FIG. 2, the user holds the body 18 by hand, pressesthe skin touch switch 20 against a target region where administration isto be carried out, and pushes the switch 17. Then, the injection needle1 is inserted into the skin. When about 0.5 sec has passed after theneedle insertion, the motor 13 starts to rotate, and the rotationpropagates to the shaft screw 12. The inside of a drug solution pushpiston 9 is engaged with a screw thread formed at the surface of a shaftscrew 12, whereby the piston 9 is movable forward and backward in thesyringe 8 when the shaft screw 12 rotates. Therefore, when the shaftscrew 12 rotates, the drug solution push piston 9 is pushed forward.When the drug solution push piston 9 moves forward, it presses therubber 24 and the rubber 7, and further, the drug solution 5 is pushedout of the tip of the injection needle 1 to be administered into theskin.

However, when the skin touch switch 20 is not pressed, that is, when thebody 18 is not pressed against the skin, no needle insertion norinjection of drug solution are carried out even if the switch 17 ispressed, as already described above. Once the switch 17 is pressed, itcontinues to operate.

The time until the motor 13 starts to operate after needle insertion,and the duration of drug injection by the motor 13, i.e., the amount ofdrug solution to be injected, are previously incorporated in themicroprocessor 100 shown in FIG. 4, and these operations are carried outaccording to instructions from the microprocessor 100.

Further, replacement of the syringe 8 is carried out as follows.

After administration, the injection needle 1 is surely housed in thebody 18. When the reset switch 122 is pressed in this state, the motor13 and the shaft screw 12 rotate so as to pull the drug solution pushpiston 9 back into the body. Then, the body cap 21 is removed in thestate where the drug solution push piston 9 is housed in the body, theneedle cap 101 (similar to that shown in FIG. 6) is attached to theinjection needle 1, and the injection needle 1 is twisted to be removed.Next, the syringe cap 4 is removed, and the syringe 8 is removed so asto be replaced with a new one. After syringe replacement, the syringecap 4 is set, and the injection needle 1 covered with the needle cap 101is set. Thereafter, the needle cap 101 is removed, and the body cap 21is attached to the body 18, whereby the administration instrument goesinto the stand-by for administration.

Next, a description will be given of automatic dissolving, automaticmixing (shaking), automatic air-releasing, and automatic administration,with reference to FIGS. 3 and 4.

The inside of the syringe 8 is partitioned by the rubber 7 and therubber 24 into two rooms, and the respective rooms are filled with thedrug solution 22 and the powder preparation 23. Further, the injectionneedle 1 is previously attached to the tip of the syringe 8.

When the user holds the body 18 by hand and presses the dissolvingswitch 121 with the injection needle 1 turning upward, the motor 13rotates, and the shaft screw 12 directly connected to the axis of themotor 13 rotates. A screw thread is formed on the surface of the shaftscrew 12 so as to engage with a thread formed inside the drug solutionpush piston 9, and the tip of the drug solution push piston 9 is fixedto the rubber 24 with a screw.

Accordingly, when the shaft screw 12 rotates, the rubber 24 united withthe drug solution push piston 9 starts to move toward the tip of theinjection needle. That is, when the axis of the motor 13 rotates, theshaft screw 12 rotates, and the rotation is converted into a thrust thatmoves the rubber 24 in the syringe 8 toward the injection needle 1 bythe drug solution push piston 9.

Next, when the rubber 24 is pushed, the drug solution 22 is compressedand pushes the rubber 7 forward. When the rubber 7 reaches a positionslightly ahead of a protrusion 25 of the syringe, the drug solution 22passes through the space that is formed by the protrusion 25 of thesyringe and, further, goes over the rubber 7 and flows into the roomwhere the powder preparation 23 exists. At this time, the rubber 7 doesnot move even when the rubber 24 is pressed toward the injection needle1 until all of the drug solution 22 flows into the room of the powderpreparation 23.

After the rubber 24 is pressed toward the injection needle 1 and all ofthe drug solution 22 flows into the room of the powder preparation 23,the rubber 24 contacts the rubber 7. On the other hand, the drugsolution 22 that has flowed into the room of the powder preparation 23starts to gradually dissolve the powder preparation 23. Themicroprocessor 100 shown in FIG. 4 monitors the time from when the motor13 starts to rotate to when all of the drug solution 22 flows into theroom of the powder preparation 23. Up to this point the automaticdissolving has been described.

As described above, since the microprocessor 100 shown in FIG. 4monitors the time required for a series of operations up to theautomatic dissolving, it instructs automatic mixing (shaking) after theautomatic dissolving is completed.

Hereinafter, this operation will be described.

The body 18 is positioned so that the injection needle 1 turns upward.In FIG. 4, when the microprocessor 100 judges that the automaticdissolving is completed, the microprocessor 100 outputs an instructionto rotate the motor 16. When the motor 16 rotates, the movable screw 15directly connected to the axis of the motor 16 rotates.

A screw thread is formed on the surface of the movable screw 15 so as toengage with a thread formed inside the inner cap 14. The inner cap 14 isfixed to a part of the inner case 10 with a screw, and is freely movablein combination with the inner case 10, by a predetermined stroke in thedirection parallel to the longitudinal direction of the body 18, in thebody 18. That is, when the axis of the motor 16 rotates, the movablescrew 15 rotates, and the rotation is converted into a thrust that movesthe inner case 10 forward in the body 18 by the inner cap 14.

A plate-shaped protrusion 19 is formed on a part of the inner case 10.Further, a photocoupler 11 is formed on the inside of the body 18. Asthe inner case 10 moves toward the injection needle 1 with rotation ofthe motor 16, the plate-shaped protrusion 19 also moves in the samedirection. When the plate-shaped protrusion 19 reaches the position ofthe photocoupler 11, the microprocessor 100 outputs an instruction torotate the motor 16 in the direction inverse to the previous rotation,according to a detection signal of the photocoupler 11. Then, the innercase 10 moves up to the initial position. When the inner case 10 reachesthe initial position, the microprocessor 100 again outputs aninstruction to normally rotate the motor 16 as before. Then, the innercase 10 starts to move toward the injection needle 1.

By repeating the above-mentioned operation several times, the inner case10 is shaken. Consequently, the syringe 8 attached to the inner case 10is shaken, whereby the dissolved drug solution in the syringe 8 isshaken.

The shaking time of the syringe 8 and the number of times the syringe 8is shaken (for example, 10 sec or below, and five to twenty times) havepreviously been incorporated as a program in the microprocessor 100 sothat an optimum state can be obtained according to the drug solution tobe handled. The stroke during the shaking is made so that the injectionneedle 1 never goes out of the body cap 21 attached to the body 18.

Next, automatic air-releasing and automatic administration will bedescribed.

Initially, automatic air-releasing is incorporated as a program in themicroprocessor 100 so as to be carried out subsequently to the automaticshaking.

During the air-releasing, the body is positioned with the injectionneedle 1 turning upward, as in the dissolving and shaking. Theair-releasing is carried out with the injection needle 1 protruding fromthe body cap 21.

After the shaking, the microprocessor 100 outputs an instruction tonormally rotate the motor 16. Then, as described above, the movablescrew 15 rotates, and the inner cap 14 moves the inner case 10 towardthe injection needle 1, and consequently, pushes the injection needle 1out of the body cap 21. During the air-releasing, even if theplate-shaped protrusion 19 formed at a part of the inner case 10 passesthe photocoupler 11 formed on the inside of the body 18, themicroprocessor 100 does not accept a signal at this time.

At a point in time when the injection needle 1 goes out of the body cap21, the microprocessor 100 stops rotation of the motor 16, and thenoutputs an instruction to normally rotate the motor 13. As alreadydescribed for the automatic dissolving, when the motor 13 normallyrotates, the rotation makes the shaft screw 12 rotate, and makes thedrug solution push piston 9 move toward the injection needle 1.

Since the operation up to the shaking has been ended, the rubber 7 andthe rubber 24 contacting each other moves toward the injection needle 1,pushes out the drug solution in the syringe 8, and further, pushes outthe air in the syringe 8. Since the amount of air to be pushed out atthis time depends on the amount of operation of the drug solution pushpiston 9, i.e., the rpm of the motor 13, the rpm of the motor 13 ispreviously incorporated in the microprocessor 100 as a program.

Next, automatic administration will be described. The user holds thebody 18 by hand, and presses the skin touch switch 20 against a targetregion, and presses the switch 17. Then, automatic needle insertion iscarried out. Since the detail has already been described, repeateddescription is not necessary.

After the automatic needle insertion, the microprocessor 100 outputs aninstruction to normally rotate the motor 13. Then, the shaft screw 12rotates, and the drug solution push piston 9 pushes the rubber 24 andthe rubber 7, and further, pushes the drug solution. The drug solutionis administered to the skin through the inside of the injection needle1. The speed of administering the drug solution at this time can bevariably set by the setting switch 26. Further, since the motor 13 iscontrolled at a constant speed by the microprocessor 100, it is possibleto make the amount of drug solution to be injected per unit timeconstant.

When the skin touch switch is removed from the skin during theadministration, the microprocessor 100 outputs an instruction to stopthe rotation of the motor 13, whereby the drug solution push piston 9stops, and consequently, injection of the drug solution from the needle1 stops. Further, the injection needle 1 goes into the automatic needleremoval state after a few seconds from when rotation of the motor 13stops, and then it is housed in the body 18. At this time, the reasonwhy the injection needle 1 is left for a few seconds is because the drugsolution may leak from the tip of the injection needle 1 due to pressurethat has been applied to the drug solution push piston 9 even if thepiston 9 is suddenly stopped during the administration. The time haspreviously been stored in the microprocessor.

After the administration is completed, the microprocessor 100 outputs aninstruction to perform the operation of automatic needle removal. Anappropriate time from the completion of administration to the automaticneedle removal should be about 6 sec, considering existing data that thetime from when injection of the drug solution is stopped to when leakageof the drug solution from the tip of the needle is completely stopped isabout 5 sec.

A series of operations from the automatic needle insertion and theautomatic administration to the automatic needle removal may beperformed by only pressing the skin touch switch 20 against the skinwithout pushing the switch 17. For this purpose, the microprocessor 100should monitor the time periods required for the respective operationsfrom when the skin touch switch 20 touches the skin, whereby all of theoperations can be carried out at appropriate timings. Further, themicroprocessor 100 may sound a buzzer 27 with varying the tone accordingto the timings of the respective operations, i.e., needle insertion,administration, completion of administration, needle removal, etc.,whereby a person having bad eyesight as well as a person having normaleyesight can recognize the operation state by the sound, and they canuse the administration instrument with peace in mind.

Further, if the user forgets about attaching the injection needle 1 whenperforming dissolving or administration, dissolving or administrationare prevented by the operation as follows.

This operation will be described with reference to FIGS. 2, 3, and 4.

With reference to FIG. 4, the driver of the motor 13 is provided with adetection resistor 123 for converting a current that flows in the motor13 into a voltage. The voltage is compared with a reference voltage thatis previously set by a reference voltage setting resistor 124 and areference voltage setting resistor 125 in a comparator 126. When theuser presses the switch 17 to perform dissolving or administrationwithout the injection needle, the motor 13 tries to normally rotate insuch a direction that the drug solution push piston 9 pushes out thedrug solution 9. However, in the rooms filled with the drug solution 5(22) and the powder preparation 23, respectively, there is no way tomake the air or the drug solution escape because the injection needle 1is not attached, and thereby the pressure increases suddenly. However,the motor 13 tries to continue the rotation, more current flows into thedetection resistor 123, and thereby the voltage of the detectionresistor 123 increases. When the voltage of the detection resistor 123exceeds the voltage that is set by the reference voltage settingresistor 124 and the reference voltage setting resistor 125, the outputof comparator 126 instructs the microprocessor 100 to stop the motor 13.Of course, a program for giving the above-mentioned instruction ispreviously incorporated in the microprocessor 100.

APPLICABILITY IN INDUSTRY

As described above, the automatic administration instrument for medicaluse according to the present invention is useful as an administrationinstrument for administering drug solutions such as growth hormone,insulin, and the like.

What is claimed is:
 1. An automatic administration instrument formedical use for injecting a drug solution filled in a syringe, theautomatic administration instrument comprising: a body for housing thesyringe and an injection needle; a first motor for sliding the syringewithin the body in a first direction and in a second direction oppositeto the first direction, the first direction being a direction in which atip of the injection needle faces when the injection needle protrudesfrom the body; a second motor for operating the syringe to administerthe drug solution; a skin touch switch which detects whether the bodycontacts a body region of the patient to which the drug solution is tobe administered; and an administration switch provided on the body, theadministration switch being configured to activate the first motor andthe second motor in sequential order when the administration switch isoperated while the skin touch switch detects that a part of an exteriorof the body is pressed against the body region the patient to which thedrug solution is to be administered, wherein the administration switchactivates the first motor to drive the syringe in the first directionsuch that the injection needle protrudes from the body to perform theinjection needle insertion into the body region of the patient while thepart of the exterior of the body is pressed against the body region ofthe patient, and thereafter activates the second motor to administer thedrug solution, and after the drug solution is administered reactivatesthe first motor to slide the syringe in the second direction such thatthe protruding injection needle is retracted into the body while thepart of the exterior of the body is pressed against the body region ofthe patient, wherein there is a period of time from the completion ofadministration by stopping the second motor to the start of an automaticneedle removal operation by reactivating the first motor, and wherein,when the skin touch switch is removed from the skin during theadministration of the drug solution, the second motor stops, and afterthe period of time from the stop of the second motor, the first motorreactivates the automatic needle removal operation.